A CRISPR-Cas9 tool to explore the genetics of Bacillus subtilis phages.

Here, we present pRH030, a new CRISPR-Cas9 tool for the genetic engineering of Bacillus phages and beyond. It is based on the Streptococcus pyogenes cas9 with its native constitutive promoter, tracrRNA, and a gRNA precursor. The constitutive expression of Cas9 was conducive to the inactivation of viral attackers and enhanced phage mutagenesis efficiency up to 100%. The gRNA precursor can be built up to an artificial CRISPR array with up to 5 spacers (target sequences) assembled from ordinary oligonucleotides and directly cloned into pRH030. Required time and resources remain comparable to a single gRNA cloning. These properties make pRH030 an attractive new system for the modification of Bacillus phages and qualify it for research beyond genetic construction.

Ultrafast domain wall dynamics in magnetic nanotubes and nanowires.

The dynamic properties of magnetic domain walls in nanotubes and in cylindrical nanowires can be significantly different from the well known domain wall dynamics in thin films and in flat thin strips. The main differences are the occurrence of chiral symmetry breaking and, perhaps more importantly, the possibility to obtain magnetic domain walls that are stable against the usual Walker breakdown. This stability enables the magnetic field-driven propagation of the domain walls in nanotubes and nanocylinders at constant velocities which are significantly higher than the usual propagation speeds of the domain walls. Simulations predict that the ultrafast motion of magnetic domain walls at velocities in a range above 1000 m s-1 can lead to the spontaneous excitation of spin waves in a process that is the magnetic analog of the Cherenkov effect. In the case of solid cylindrical wires, the domain wall can contain a micromagnetic point singularity. We discuss the current knowledge on the ultrafast dynamics of such Bloch points, which remains still largely unexplored.

Spin-torque-induced dynamics at fine-split frequencies in nano-oscillators with two stacked vortices.

The gyrotropic rotation around the equilibrium position constitutes the fundamental excitation of magnetic vortices in nanostructures. The frequency of this mode varies with material and sample geometry, but is independent of the vortex handedness and its core direction. Here, we demonstrate that this degeneracy is lifted in a spin-torque oscillator containing two vortices stacked on top of each other. When driven by spin-polarized currents, such devices exhibit a set of dynamic modes with discretely split frequencies, each corresponding to a specific combination of vorticities and relative core polarities. The fine splitting occurs even in the absence of external fields, demonstrating that such devices can function as zero-field, multi-channel, nano-oscillators for communication technologies. It also facilitates the detection of the relative core polarization and allows for the eight non-degenerate configurations to be distinguished electrically, which may enable the design of multi-state memory devices based on double-vortex nanopillars.

Conjugative reporter system for the use in Bacillus licheniformis and closely related Bacilli.

Bacillus wild-type strains are genetically difficult to manipulate, and thus, the options for rational strain investigation and design are limited. Here, we present a set of small conjugative shuttle vectors for the use in Bacillus licheniformis and related, genetically difficult accessible wild-type strains. The vector set comprises the modular general-purpose vector pV2 and its derivatives pV3SDlacZ and pV3lacZ. The pV3 vectors are designed for the investigation of transcriptional and translational activities of regulatory regions like promoters and ribosomal binding sites (RBS). The vector set has been tested for investigating gene regulation under aerobic and anaerobic conditions.

Operative versus non-operative treatment for two-part surgical neck fractures of the proximal humerus.

INTRODUCTION: Aim of this study was to evaluate outcomes of operative as compared to conserveative treatment for two-part humerus fractures at the surgical neck. METHODS: Data from a prospective multi-centre cohort study on four treatment options (conservative treatment and three implants, i.e. LPHP, PHILOS and PHN) for proximal humerus fractures were evaluated in this post hoc analysis. All patients with two-part fractures of the surgical neck (AO types A2, n = 54 and A3, n = 110) were identified and included for the analysis. All operatively treated patients were gathered and compared to those receiving conservative treatment. Primary outcome parameters were pain, range of motion and absolute and relative Constant scores at 3, 6 and 12 months following injury and coronal plane alignment at 12 months. RESULTS: Operative (n = 133) and non-operative (n = 31) groups were comparable with regard to all parameters assessed including mean age (62.9 vs. 65.6, P = 0.479), gender (27 vs. 29 % male, P = 0.826) and fracture distribution (65 vs. 77 % A3 type, P = 0.207). 26 of the 31 conservatively treated and 103 of the 133 operatively treated patients (84 and 77 %, respectively) were available for final follow-up. There was a continuous improvement for all outcome parameters in both treatment groups (P < 0.001). Operative treatment resulted in a more effective reduction of pain at 3 months (51 vs. 76 % reporting pain at fracture site, P = 0.03) and a reduction of coronal plane malalignment. Both range of motion and Constant scores were, however, comparable in both groups at all follow-up visits. Relative and absolute Constant scores were generally excellent at final follow-up (74 vs. 74, P = 0.528 and 89 vs. 91, P = 0.494, respectively). CONCLUSIONS: Both non-operative treatment and operative treatment using modern implants (LPHP, PHILOS and PHN) can be considered safe and effective treatment options for two-part fractures of the proximal humerus. Operative treatment may result in better range of motion and reduced pain in the early postoperative course of treatment.

Disentangling the physical contributions to the electrical resistance in magnetic domain walls: a multiscale study.

We analyze the origin of the electrical resistance arising in domain walls of perpendicularly magnetized materials by considering a superposition of anisotropic magnetoresistance and the resistance implied by the magnetization chirality. The domain wall profiles of L1(0)-FePd and L1(0)-FePt are determined by micromagnetic simulations based on which we perform first-principles calculations to quantify electron transport through the core and closure region of the walls. The wall resistance, being twice as high in L1(0)-FePd than in L1(0)-FePt, is found to be clearly dominated in both cases by a high gradient of magnetization rotation, which agrees well with experimental observations.

Ultrafast nanomagnetic toggle switching of vortex cores.

We present an ultrafast route for a controlled, toggle switching of magnetic vortex cores with ultrashort unipolar magnetic field pulses. The switching process is found to be largely insensitive to extrinsic parameters, like sample size and shape, and it is faster than any field-driven magnetization reversal process previously known from micromagnetic theory. Micromagnetic simulations demonstrate that the vortex core reversal is mediated by a rapid sequence of vortex-antivortex pair creation and annihilation subprocesses. Specific combinations of field-pulse strength and duration are required to obtain a controlled vortex core reversal. The operational range of this reversal mechanism is summarized in a switching diagram for a 200 nm Permalloy disk.

Magnetic vortex core reversal by excitation with short bursts of an alternating field.

The vortex state, characterized by a curling magnetization, is one of the equilibrium configurations of soft magnetic materials and occurs in thin ferromagnetic square and disk-shaped elements of micrometre size and below. The interplay between the magnetostatic and the exchange energy favours an in-plane, closed flux domain structure. This curling magnetization turns out of the plane at the centre of the vortex structure, in an area with a radius of about 10 nanometres--the vortex core. The vortex state has a specific excitation mode: the in-plane gyration of the vortex structure about its equilibrium position. The sense of gyration is determined by the vortex core polarization. Here we report on the controlled manipulation of the vortex core polarization by excitation with small bursts of an alternating magnetic field. The vortex motion was imaged by time-resolved scanning transmission X-ray microscopy. We demonstrate that the sense of gyration of the vortex structure can be reversed by applying short bursts of the sinusoidal excitation field with amplitude of about 1.5 mT. This reversal unambiguously indicates a switching of the out-of-plane core polarization. The observed switching mechanism, which can be understood in the framework of micromagnetic theory, gives insights into basic magnetization dynamics and their possible application in data storage.

Peritonitis in childhood: clinical relevance of cytokines in the peritoneal exudate.

BACKGROUND: The aim of the study was to assess pro-inflammatory cytokine (tumor necrosis factor alpha [TNF-alpha], interleukin 6 [IL-6]) and anti-inflammatory cytokine (interleukin 10 [IL-10]) responses in children with peritonitis secondary to hollow viscus perforation, and to evaluate the influence of peritoneal microbial status on cytokine expression and morbidity. METHODS: The peritoneal fluid of 13 children with perforated appendicitis was examined with qualitative analysis of bacteria, and measurement of cytokine levels, which were compared to cytokine plasma levels, over a five-day period following operation. RESULTS: All fluid specimens showed permanently elevated levels of TNF-alpha and IL-10. IL-6 tended to decrease to normal levels by the 5th postoperative day. Peritoneal exudate levels of TNF-alpha and IL-10 were more than 100 - 1000 times greater than those in plasma. The most common bacterial species isolated in the peritoneal fluid was Escherichia coli. Despite persisting high cytokine concentrations and bacterial load of the peritoneal cavity for 5 days postoperatively, the children recovered uneventfully and the systemic signs of infection disappeared rapidly. CONCLUSION: Neither the bacterial nor the pro-inflammatory cytokine load of the peritoneal cavity proved to be associated with the clinical course. We hypothesize that in peritonitis in childhood a significant and clinically relevant cytokine-mediated inflammatory response is compartmentalized in the peritoneal cavity. Therefore adjuvant surgical measures in addition to appendectomy and intraoperative debridement seem not to be necessary, at least for peritonitis due to perforated appendicitis in children.

Specificity patterns indicate that auxin exporters and receptors are the same proteins.

A study of transport and action of synthetic auxin analogues can help to identify transporters and receptors of this plant hormone. Both aspects--transportability and action on growth--were tested with 2-naphthoxyacetic acid (2-NOA) and compared across several plant species. 2-NOA stimulates elongation effectively at low concentrations in petioles of the gymnosperm Ginkgo biloba L., in hypocotyls or internodes of the dicot legumes, mung bean (Vigna mungo L.) and pea (Pisum sativum L.), in cotyledons of onion (Allium cepa L.) and in leaf bases of chive (Allium schoenoprasum L.), the latter two of the monocot order Asparagales. In contrast, elongation of coleoptile segments of maize (Zea mays L.) is poorly responsive to 2-NOA. Significant auxin-like transport of 2-NOA was observed in segments of mung bean hypocotyls, pea internodes, and chive leaf bases, but not in segments of the grass coleoptiles. Thus, for the two assays, elongation and polar transportability, the same difference in ligand specificity was observed between the grass and all other species assayed. This finding supports the hypothesis that a common protein mediates auxin efflux as well as auxin action on elongation.

Predictors of humeral head ischemia after intracapsular fracture of the proximal humerus.

The purpose of this study was to evaluate predictors of fracture-induced humeral head ischemia. Between February 1998 and December 2001, 100 intracapsular fractures of the proximal humerus, treated by open surgery, were included in a prospective surgical evaluation protocol (mean age, 60 years; minimum, 21 years; maximum, 88 years; 45 men; 57 right shoulders). Fracture morphology was assessed following a structured questionnaire and based on radiographic and intraoperative findings. Perfusion was assessed intraoperatively by observation of backflow after a borehole was drilled into the central part of the head in all shoulders and by intraosseous laser Doppler flowmetry in 46. Good predictors of ischemia were the length of the metaphyseal head extension (accuracy, 0.84 for calcar segments <8 mm), the integrity of the medial hinge (accuracy, 0.79 for disrupted hinge), and the basic fracture pattern (accuracy, 0.7 for combined types 2, 9, 10, 11, and 12). Moderate and poor predictors of ischemia were fractures consisting of four fragments (accuracy, 0.67), angular displacement of the head (accuracy, 0.62 for angulations over 45 degrees ), the amount of displacement of the tuberosities (accuracy, 0.61 for displacement over 10 mm), glenohumeral dislocation (accuracy, 0.49), head-split components (accuracy, 0.49), and fractures consisting of three fragments (accuracy, 0.38). When the above criteria (anatomic neck, short calcar, disrupted hinge) were combined, positive predictive values of up to 97% could be obtained. The most relevant predictors of ischemia were the length of the dorsomedial metaphyseal extension, the integrity of the medial hinge, and the basic fracture type determined with the binary description system.

Direct observation of the single-domain limit of Fe nanomagnets by spin-polarized scanning tunneling spectroscopy.

We have investigated the magnetic structure of self-organized Fe islands on W(001) by means of spin-polarized scanning tunneling spectroscopy (Sp-STS). Single-domain, simple vortex, and distorted vortex states have been observed. The high resolution magnetic images were used to experimentally determine the single-domain limit. The experimental structures were compared with results of micromagnetic calculations confirming the ground state nature of the experimental configurations. The single-domain limit directly observed with Sp-STS is consistent with theoretical predictions.

Biomechanical and biological considerations relating to the clinical use of the Point Contact-Fixator--evaluation of the device handling test in the treatment of diaphyseal fractures of the radius and/or ulna.

The Point Contact-Fixator (PC-Fix) was designed as part of the developmental evolution of more biological devices for internal fixations. It is a device characterized by minimal contact to the underlying periosteum and bone, hereby minimizing potential damage to perfusion. A multicentre handling test was conducted in 1993 and 1994 in six hospitals to assess its performance. A total of 83 fractured forearm bones (34 radii and 49 ulnae) in 52 patients were stabilized with a PC-Fix. The mean age of the patients was 37 years. There were 24 AO type A, 24 type B and 5 type C fractures. Nine fractures were open. Mean follow-up was 15.6 months; follow-up was 100%. All 21 surgeons involved considered the use of the PC-Fix self-explanatory and relatively easy. Handling difficulties were mainly related to insertion of the monocortical screws. In particular, the precision required for insertion, the inability to incline the screw and the inability to pull the plate to the bone using the screw were considered hard to deal with. Stripping of the hexagonal slot was a problem at removal of the implant, possibly related to overtightening of the screws at insertion. In 76 of 83 bones (49 of 53 forearms), the fractures united without additional surgery. The healing pattern typically showed early callus formation bridging the fracture, followed by progressive mineralization of the central radiolucent line. Complications included one infection, one late displacement and four delayed unions, all requiring revision surgery. In 8 forearms, plate removal was performed after a mean of 10.3 months. Two refractures occurred after removal of the implant 6 and 7 months postoperatively. In conclusion, the practical handling of the new implant was straightforward and easily learnt. The treatment failures observed were related to technical and strategic errors. We consider that, when using devices with a locking compression principle, a minimum number of three screws should be placed on each side of the fracture, that interfragmentary compression of simple fractures is desirable in order to increase stability and that, contrary to in vivo animal studies, early plate removal is not indicated. The trend in fracture fixation is to improve the biomechanical and biological properties of operating technique and the devices used. The PC-Fix has proven a useful step in the right direction in this evolutionary process.

[Open arthrolysis in preserved joint surface geometry]. / Offene Ellenbogenarthrolyse bei erhaltener Gelenkflächengeometrie.

This review article discusses the operative treatment options for release of essentially extracartilaginous contractures of the elbow (referred to as extrinsic contractures). Indications, preoperative work-up, specific operative strategy and techniques, rehabilitation, possible complications, and results are discussed and compared. Special reference is made to the technique of sequential surgical release based on the transhumeral approach. This technique makes it possible to optimize the articular offset while preserving the static and dynamic stabilizers of the joint. Treatment of contractures of the elbow remains dangerous and delicate. It deserves experienced surgical handling in order to avoid complications. Thus, it remains to be hoped that qualified management will help to improve the relatively mediocre functional results.

Surgical landmarks to determine humeral head retrotorsion for hemiarthroplasty in fractures.

Malrotation has been suggested as a cause of failure of hemiarthroplasty of the proximal humerus. Placing a shoulder prosthesis in relationship to the bicipital groove might reproduce individual anatomy more reliably than using a standardized retrotorsion. The purpose of this study was to determine criteria for accurate adjustment of retrotorsion even when the proximal bicipital groove is destroyed, as is the case in fractures. The distance of the humeral head equatorial plane to the center of the bicipital groove was measured by high-resolution computed tomography at 4 levels (proximal and distal with 2 intermediate levels). The distal distance was considered to correspond to available references in fracture cases. The mean proximal distance was 8.0 mm (10th percentile, 6.2 mm; 90th percentile, 9.8 mm), and the mean distal distance was 8.5 mm (10th percentile, 7.1 mm; 90th percentile, 9.9 mm). As to the clinical relevance, there was no statistically significant difference between distances. For practical purposes in fracture indications, it is adequate to adjust the retrotorsion of the prosthetic component to the distal bicipital groove.

[Glenohumeral joint. Anatomical aspects and implications for prosthesis design]. / Die Schultergelenkpfanne. Anatomische Aspekte und Implikationen für das Prothesendesign.

Knowledge of normal anatomy and kinematics of the glenohumeral joint as well as analysis of the pathoanatomic changes that occur during the course of the disease is the condition for successful patient management. This review article critically discusses the most relevant geometrical variables. Systematically, normal anatomy, pathologic anatomy, and the implications for prosthetic design and implantation are presented. The most important aspects concerning the size and shape of the glenoid, the inclination of the articular surface in the horizontal and frontal planes, as well as the geometry of the scapular neck are discussed. The accumulated knowledge is of immediate practical use and might stimulate researchers and manufacturers to develop more adequate glenoid components.

Cotton-induced pseudotumor of the femur.

Twenty-five years prior to presentation a 41-year-old man had a femoral fracture stabilized with a 4.5 mm AO/ASIF steel plate. The femur healed uneventfully and the patient was asymptomatic for the following 20 years. He then noticed a slow-growing swelling of the left thigh associated with a degree of weakness. Radiographs of the femur 25 years after fracture stabilization showed a massive expansive osteolytic process surrounded by a rim of bone. Magnetic resonance imaging (MRI) confirmed the presence of a large tumor. Since malignancy could not be excluded the patient underwent incisional biopsy. The histologic findings were nonspecific. Because of persistent symptoms the lesion was marginally excised. Intraoperatively a folded cotton sponge was found adjacent to the femur. Histopathologic investigation confirmed a foreign body reaction probably related to the retained cotton sponge. Reactive, foreign-body-induced change may mimic bone and or soft tissue malignancies.

Auxin-induced elongation of short maize coleoptile segments is supported by 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one.

Endogenous extractable factors associated with auxin action in plant tissues were investigated, especially their effects on elongation of 1-mm coleoptile segments of maize (Zea mays L.), in the presence of saturating 10 microM indole-3-acetic acid (IAA). The relative growth response, to auxin alone, was much smaller in segments shorter than 2-3 mm compared to 10-mm segments. Fusicoccin-induced elongation, however, was less affected by shortening the segments. A reduced auxin response may result from the depletion through cut surfaces of a substance required for IAA-mediated growth. Sucrose, phenolics like flavonoids, and vitamins were ruled out as the causal factors. A partially purified methanol extract of maize coleoptiles supported longterm, auxin-controlled elongation. The active material was also found among substances bleeding from scrubbed maize coleoptiles. The active factor from maize was further purified by HPLC and characterised by the UV spectrum and its pH shift. This factor was identified as 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one (DIMBOA) by mass spectroscopy. Activity tests confirmed that pure DIMBOA from other sources sustained auxin-induced elongation of short maize coleoptile segments. However, DIMBOA only partially restored the activity lost from short segments. This indicates that an additional factor, other than DIMBOA, is required. Extracts from Avena or Cucurbita did not contain the factor DIMBOA; it was active on maize elongation, but not on Avena coleoptiles or Cucurbita hypocotyls. This narrow specificity and the lack of DIMBOA action in short-term tests with maize indicate that DIMBOA is not the general auxin cofactor but may specifically "spare" the co-auxin in maize.

Die steife Schulter.

Painful stiffness of the shoulder is an ill-defined||| clinical entity that is difficult to assess and delicate to treat. The||| nomenclature used is broad and includes terms such as frozen shoulder, adhesive||| capsulitis, focal algodystrophy, stiff shoulder, contracted shoulder, and||| others. Apart from its idiopathic form, the disease can be initiated by trauma,||| infection, tumour, radiation, systemic and local metabolic disturbances.||| Pathoanatomically, the common denominator is an inflammatory vascular||| proliferation followed by thickening, scarring, and retraction of the joint||| capsule. The inflammatory process often starts at the rotator interval and may||| extend to the subacromial space. Clinical diagnosis is based on history and||| physical examination. Generally the onset of pain precedes the perception of a||| reduced range of motion by weeks or months. In early stages of the disease, the||| inflammatory type of pain dominates, i.e., the patient's main complaint ist||| pain at night. In the later stage, range of motion gradually decreases.||| Patients do not often complain about reduced motion, probably because of its||| slow onset. Treatment options are a combination of mobilisation exercises with||| intra-articular steroids, hydraulic distension of the joint capsule,||| manipulation under anaesthesia, arthroscopic and/or open arthrolysis. The||| appropriate choice of protocol is just as important as its correct timing. In||| the inflammatory phase, aggressive treatment protocols are probably||| contraindicated. Complications of invasive protocols are rare but deleterious||| and therefore have to be taken into consideration. New anti-anglogenetic agents||| may enhance functional results and shorten the rehabilitation||| phase.

Treatment of tibial plateau fractures with small fragment internal fixation: a preliminary report.

OBJECTIVE: To evaluate the use of small fragment implants for fractures of the proximal tibia. DESIGN: Retrospective. SETTING: Level I trauma center. PATIENTS/PARTICIPANTS: Seventeen patients with AO Classification Type B and C fractures of the proximal tibia. Two patients were lost to follow-up. INTERVENTION: After atraumatic dissection and open reduction, fracture stabilization was accomplished with the use of the AO/ASIF small T-plate (3.5-millimeter system). In two patients a medial uniplanar external fixator was applied as additional fixation. In six patients a cancellous autograft was performed. MAIN OUTCOME MEASUREMENTS: At an average follow-up of forty-two months (range, 24 to 75 months), all patients were evaluated radiographically and functionally. The incidence of local complications was specifically recorded. RESULTS: Postoperatively, the radiographs showed 86.7 percent anatomic or near anatomic reduction with respect to the articular joint surface. In three separate patients condylar widening, condylar narrowing or varus deformity was evident. In one patient, a minimal secondary displacement of less than two millimeters was observed before bony healing. All fractures healed within twelve weeks. At the latest follow-up, there were 53.3 percent excellent, 33.3 percent good, and 13.3 percent fair results. There were no infection or soft tissue complications. CONCLUSIONS: The use of small fragment implants combined with atraumatic soft tissue dissection potentially offers good results for the treatment of fractures of the proximal tibia. These initial results suggest that this technique may have the advantage of anatomic reduction while comparing favorably with less invasive methods regarding radiologic and functional outcome as well as incidence of complications.